The present invention relates to pharmaceutically acceptable salts of 2-diethylamino-1-methylethyl cis-1-hydroxy-(bicyclohexyl)-2-carboxylate and particularly to a process for their preparation.
2-diethylamino-1-methylethyl cis-1-hydroxy-(bicyclohexyl)-2-carboxylate, also known by the common international name of Rociverine or "Rociverinum", is in therapy as an antispasmodic drug (U.K. Patent No. 1.167.386).
It is prepared by reacting cis-1-hydroxy-(biciclohexyl)-2-carboxylic acid with 1-diethylamino-2-chloropropane in the presence of an acceptor of hydrogen chloride; by this reaction a mixture of position isomers is formed. It is then subjected to a thermal treatment which causes isomerization to take place. Thereafter, the product is purified by distillation (see Italian Patent Application No. 30163 A/78), the therapeutically active and desired isomer is obtained, having the formula: ##STR1##
The thus obtained prrduct is in the form of a yellow oily liquid, not soluble in water, having a gaschromatographic purity of 98%, which is used as such in the pharmaceutical practice for the preparation of vials, tablets and suppositories. Of course, for pharmaceutical use, an oily substance is more difficult to handle, both in the preparation of the desired formulations, and as regards its storage, unless particular care is taken.